Process and apparatus for drawing sheet-glass.



No.,836,439 PATENTED NOV. 20, 190

' I. w. GOLBURN.

PROCESS AND APPARATUS FOR DRAWING SHEET GLASS.

APPLICATION FILED JULY 10. 1006.

0 SHEETS-SHEET 1 2/911?" use: Q!

No. 836,489. PATENTED NOV. 20, 1906. I. W. GOLBURN.

PROCESS AND APPARATUS FOR DRAWING SHEET GLASS.

APPLICATION FILED JULYlO. 1906.

6 SHEETSSHEET 2 We 131 uses fiaw/ a. 5444;

'No. 836,439. PATENTED NOV. 20,1906. I. W. GOLBURN.

PROCESS AND APPARATUS FOR DRAWING SHEET GLASS.

APPLICATION FILED JULY 10. 1906.

6 SHEETS-SHEET 3- 23 i 511 eons 9km; A

PATENTED NOV. 20, 1906.

I. W. GOLBURN.

PROCESS AND APPARATUS FOR DRAWING SHEET GLASS.

APPLICATION FILED JULY 10. 1906.

8 SHEETS-SHEET 4.

- LWZM} wlw y/(r7 v M4) 22" Mom 14; lb

No. 836,439. PATENTED NOV. 20, 1906. I. W. OOLBURN.

PROCESS AND APPARATUS FOR DRAWING SHEET GLASS.

APPLICATION FILED .TULY10,1906.

6 SHEETS-SHEET 5 No. 836,439. PATENTED NOV. 20, 1906. I. W. COLBURN.

PROCESS AND APPARATUS FOR DRAWING SHEET GLASS.

APPLIOATION FILED JULYlO. 1906.

6 SHEETSSHEET 6.

avweukw witnesses awa/flfia film, @Mm M; km;

27' umm UNITED S ATES PAT NT onn on.

invmo. w looL URN, or FRANKLlN, PENNSYL ANIA. v PROCESS .ANDVAPPV-ARATUSFoe DRAWING SHEET-GLASS."

Specification of Letters Patent. Application and July 10. 1906. seen No.325,549.

Patented Nov. 2c, 1906.

new 'and' useful Improvement in Processes and] Apparatus 'j for DrawingSheet-Glass,

which'improvement is fully set forth-in the following specification.

This invention relates to the artof drawing sheet-glass, and isapplicable to the drawing of sheets :of fixed len th, as Well as to thecontinuous drawing of t e glass in sheet form.

When an effort is made to drawa sheet of glass from amass of moltenglass, one of the great difficulties to be overcome is the tendenoy ofthe started sheet to rapidly narrow to a string or cord. Anotherifliculty lies .in the fact that it is extremely difficult to avoid theformation 'ofiwave-hke lines or striee u on the faces or surfaces of thesheet of g ass as it is drawn, which lines or striee ver-y materiallyinjure the market value of the glass and, in' fact, render itpractically unfitfor a great var ety of uses. experienced in the drawingof sheet-glass, and particularly in the. 'dr'awing of a continuoussheet. hes in the fact that the mechanism employed in handling thesheet, especially'at a time when the sheet is at all softened by theinfluence of heat, must-move in absolute unison with the movements ofthe sheet at all times, to the end that there may be no slipping action'or.r'elative movement between finish ofthe glass;

any portions of the mechanism and the surface of the sheet with whichsuch mechanism may be in contact, since such slipping action orrelative-movement between the two surfaces would be liable to slightlymar the fire- The object of the present invention is to provide a methodand means whereby a sheet of glass of uniform width can bedrawn from amass of molten glass and whereby the formation of wave-like lines orstriee upon the surfaces of the sheet, as well as the marring effect dueto contact with. any .of the mechanism, may boavoided In previous aplications filed by myself and Edgar Wash urn as i'omt inventors, saidapplications being Seria No. 248,288, filed March 3, 1905, and SerialNo. 304,555, filed March 6', 1906, there is disclosed a method andapparatus for overcoming the narrowing tendency of the sheet during thedrawing operation, which method, generally stated, conthe molten massdrawing" a sheet lateral movement in oppos te directions and away fromthe two edges A further difficulty sists in imparting. to thesurface-portion'of during the. operation of of the sheet. This isaccomplished byimmersing moving bodies, such as revolving spheres. inthe molten mass adjacent to the edges of the sheet being drawn andrevolving them in such a direction that their adjacent surfaces moveupward and outward.

The formation of ribs or striae upon the surface of the drawn sheet ofglass may be and probably is due to a variety' of causes. Among thesemay be mentioned the tendency ofthe surface of the molten glass in theworking chamber or pot when the same is exposed to the 'coolmginfluences of the external atmosphere to take or receive impressionsiron the roughened side walls of the working chamber or pot. This isparticularly true if the point where the molten glass leaves the wallsor other part of the receptacle be but a few inches from the point wherethe glass enters the sheet. Moreover, the chilling influence .of theatmosphere itself. is liable to-oause the surface of the molten glass tomore or less wrinkle or form into minute waves or ridges. These aresome, though doubtless not all, of the causes ofthe formation of ribs orstriae upon the surfaces of the sheet. Now during the operation ofdra'winga sheet of glass the tendency of the surface portion of themolten mass in the working chamber or pot is to move slowly toward andinto the sheet being drawn, so that any wave-like lines upon the surfaceof the molten mass would ultimately appear in the surface of the drawnsheet in the form of ribs or striae.

' Ihave discovered that if during the operation of drawing a sheet ofglass 'fromthe mol-.

ten mass a part of the surface portion of the molten mass has movementimparted to it in opposite directions and away from the two facesof thesheet being drawn the formation of the ribs or striee in the surfaces ofdrawn in 't e working chamber or pot should be heated to a degree abovethat which itis desired the surface of the mass shall possess at thetime when it enters the sheet and toward the, edges of only a limitedarea'of the surface of the-mol- I ten mass should be exposed to thecooling in fiuences of the atmosphere at or adjacent to the point wherethe sheet is being drawn; By thus raising the temperature of thoseportions. of the molten mass somewhat re mote from the sheet being drawnand by regulating the area of the surface of the molten mass exposed tothe cooling influences of the atmosphere it becomes possible to presentthe glass to. the formative point at a proper temperature and in theproper condition for awing into a sheet Without the formation theobjectionable ribs or striae, and .when this step is performed inconjunction with that of imparting movement in opposite directions to apart, of the surface portion of the mass away from the two faces of thesheet being drawn the sheet will be perfectly free from such ribs orstrise.

One part "of the im' en'tion in the present instance,therefore, residesin ,a method of drawing a sheet of glass from a ma of molten glass andsimultaneously imparting movement to a part offthe surface of the moltenmass away from the two faces of the sheet being'drawn, and, furthermore,the invention residesfina method of superheating portions of the moltenmass remote from the point where the sheet is bein drawn and I thenlimiting the area of the mo ten mass exposed to" the cooling'infiuencesof the atmosphere. v Preferably each of the above-mentinned steps are,racticed jointly-that is, motion'isimparted to a part of' the surface ofthem'olten mass in opposite directions and awayai rom the two faces of;the sheet being drawn, while at'the same time remote portions. of themoltenmass are superheated and the area ofthe molten. mass exposed tothe cooling influences of the atmosphere is controlled Within thedesired limits. By superheated as herein employed is meant the heatin ofthexsurface portion of the mass to a egreeabove that which it is desiredthe glass should have at the time when itr-assumes sheet form or at thetime when it passesfrom the molten mass into the Sorm of a sheet. As oneof the essential steps in drawing the-sheet of, glass the method alsoincludes ho ding the sheet to uniform width in any effective- 'way, asby imparting movement to the surface portion of the molten mass. nearthe she'ets edges in a direction away from the medial" line of the sheetand the sheet during the drawing operat1on.

For the urpose of im arting movement to. the su ace portion 0 the moltenmass on that portion of away from the surfaces or faces of the sheetduring the drawing operation I preferably employ two refiractoryrollers, with the lower portion of their peripheries immersed in thesurface of the molten mass in, the working chamber or pot, and slowlyrevolve these rolllying between the ,rollers. Preferably,

though not necessarily, the two rollers are revolved in o positedirections with their adjacent su 'ac'es moving upward. They may berevolved, however, with their adjacent surfaces moving downward; The useof such rollers serves not only to impart movement to a part of thesurface of the molten mass away from the faces of the sheet during thedrawing operation, but serves also to determine the area of the surfaceof the molten mass in-the. working chamber or pot which is more orlesstexposed to the cooling influences of the atmosphere, and thesuperheatin referred to above occurs the surface of thcmolten mass tothe rear of said rollers that is, on the sides of said rollers away fromthe sheet being drawn. This superheating may be accomplished; in anysuitable manner, as by directing heated ases of combustion against theglass and rol ers on the rear side ofsaid rollers.

uniform Width I may employ bodies ofrefractory material immersed in themolten mass adjacent to the edges of the sheet being drawn therefromandmovin in such a man.- ner as to impart an outwar .motion to that portionof the surface of the molten mass lymg immediately adjacent to the edgesof the sheet. These bodies for holding the glass to its uniform widthmay be of any suitable construction, such as revolving spheres shown inthe joint 1. plication of lnyself and Edgar Washburn, eria-l No.238,592, filed December 28, 1904, or they may be in the form of hooksofrefraetory material, such as shown in. the joint a. plication ofmyself and Edgar Washburn, S hrial No. 304,555, filed March 6, 1906. I

If a sheet of glass be drawn from t-he'r'n'o'l-v ten mass lying betweenthe rollers aforement'ioned and means be employed to impart an outwardmovement to thatportionofthei'sur face of the molten mass lyingimmediately adjacent to the edges of the sheet,thefoll'owing action ofthe molten glass willbe observed: The molten glass at and justbeneaththe-surface adjacent to the edges of the sheet will move away from thecenter line of thesheet+ that is, outward-thus serving to hold the sheetto its full width. As the sheet of glass moves upward there isdrawninto'thesheet some of the surface portion offthe molten massimmediately adjacent to the two faces of the sheet and also some ofthe-molten glass beneath the surface. At 'th'e same til-no the tworollers on the opposite sides of the sheet of glass also serve to drawsome of .he

surface portion of theniolten mass lying between the roller-sand thesheet of glass away from the sheet.

It will thus be seen that the For the purpose of holding the sheet toits too eaease result of the combined action of the drawing of the sheetand the movement of the rollers is the skimming, as it might be called,of the surface portion of the molten glass lying between the tworollers, thereby exposing a fresh portion or a new surface of moltenglass to the cooling eflect of the atmosphere. This action iscontinuous, and the result is a continuous supply of fresh glass to thesurface, which in turn is submitted to the cooling action. of theatmosphere before it passes into the sheet. A further'action of therollers is to bring a supply of fresh hot glass into the area lyingbetween the rollers and the sheet being drawn. The glass which isskimmed from the surface b the rollers and carried over by the rollersis subjected to the superheating action at the rear of the rollers andis melted down, so as to free the rollers from the mass of glassclinging thereto and place such glass in proper working condition. Theslow movement of the rollers, hereinafter referred to, afford s ampletime forthis melting down of the glass carried over by the rollers. Inorder to secure the desired results, it is necessary that the speed withwhich the sheet of glass is drawn and the speed with which the rollersare revolved should be properl regulated. This can be determined yexperience and will vary with the conditions of each particular case,depending upon the temperature of the molten mass in the working chamberor pot, the temperature of the external atmosphere, the thickness of thesheet to be drawn, 8w. Generally speaking, the speed at which the sheetis drawn will vary from six to thirty inches per minute, and therevolution of the rollers will vary from one revolution in ten minutesto one revolution in thirty minutes, and for this purpose there is ofcourse introduced into the machine suitable mechanism for adjusting thespeed of draft of the sheet and speed of the rollers. It will thus beobserved that there occurs a continuous skimming of the entire surfaceof the working chamber between the rollers, and as this skimming actionoccurs fresh glass continuously comes up from below at some pointbetween the sheet and the roller, which in turn affords a'new surface tobe subjected to the cooling influence of the atmosphere, which is inturn skimmed and passed into the sheet. This action is the same betweeneach roller and the sheet being drawn. In other words. fresh glass iscoming up from below at two places-one between each roller and thesheet. The skin or the surface of the molten mass becomes the skin orsurface of the sheet being drawn, and it is this skin or surface thatmust he kept free from the ribs or striae.

It will be understood that in the action above described all of thevarious steps are proceeding simultaneously that is, glass is beingdrawn from the surface by the moving sheet and by the rollers and freshglass is coming up to form a new surface, all of these proceedingsimultaneously. Of course the sheet of glass being drawn and the rollersaffect not onl r the immediate surface portion of the mo ten mass, butalso act to draw glass that is beneath the immediate surface, therollers also bringing hot glass to the working part of the pot betweenthe rollers. Moreover, this supply of hot glass keeps the temperatureseven and allows an even thickness of glass to be drawn. This furnishingof a new supply of hot glass from the back of the rollers to the surfaceportion of the mass between the rollers is one of the im ortantfunctions of the rollers. By revolving the rollers at the slow rate.mentioned above ample time is afforded to melt the glass from the rearsides of the rollers, and, moreover, this slow movement avoids thepossibility of air-bubbles being carried down by the rollers into themolten glass. This is important, as the presence of such bubbles wouldresult in blisters on or in the drawn sheet of glass.

In the continuous production of sheetglass the most convenient means forhandling the sheet consists of an apparatus for drawing the sheetvertically and then turning it from a vertical to a horizontal position,the turning being made overa suitable bending-roller, which ispositively driven so as to revolve in the same direction in which thesheet of glass is moving and is intended to revolve at the same rate ofspeed as the sheet moves, to the end, that there may be no relativemovement between the surfaces of the roller and of the sheet of glass.In practical operation, however, it has been found almost impossible toinsure at all times the uniform movement of the surface of apositivelydriven roller and the sheet of glass. While the two couldusually be relied upon to move synchronously, nevertheless there wouldat times occur certain relative movements between the two surfaces whichwould result in a slight marring of the fire-finish u on the glass. Ifthe movements of the re ler are made to depend upon the movements of thesheet of glass, this relative movement be tween the roller and the sheetwill be entirely obviated and the marring action due to such relativemovement avoided. ln some cases this may be accomplished by mounting thebending-roller as an idler-roller on antifrictional bearings'and causingit to be revolved slowly b the frictional contact of the moving sheet ofglass, as shown, (lescribed, and claimed in i he aforesi-iid applicationSerial No. 304,555. l have found, however, that in many instances. theweight of the roller is so great and the conditions under which theglass is drawn vary to so great an extent that it is desirable toutilize some positively-driven mechanism in driving the lOO roller andat the same time control the revolu' tion's entirely by the movement ofthe sheet of glass.

Generally stated, therefore, my invention onsists:

First. In a method'of drawing a sheet of glass by preparing a moltenmass of glass,

drawing a sheet therefrom, and sii'nultaneously imparting movement to apart of the surface portion of the molten mass in. o )po. site(lll'OClLlOHS and away from the faces of the sheet-durinp the drawingoperation;

Second. The invention consists in su erheating the surface portion ofthe mo ten mass remote from the'sheet being drawn, re-

tion of themolten mass away from the e gas of the sheet during thedrawing operation, though some other means for holding the sheet touniform width may be employed, if desired.

Third. The invention consists in'means for drawing a sheet of glass froma mass of molten glass, combined with means for iniparting movement tothe surface portion of the mass in oppositedirections and away from thefaces of the sheet being drawn. Preferably the means for thus impartingmotion to the surface of the molten mass consist'of a pair of arallelrefractory rollers hav ing their perip ieries partially lflllllkISQd inthe molten mass and revolving in opposite directions, the sheet beingdrawn from the molten mass lying between the rollers. I prefer to havethe rollers revolve so that their adjacent surfaces move upward andoutward, thouplh they may in some cases be re' volved in t e oppositedirect-ion.

Fourth. The invention consists in means for superheating the surfaceportion of the molten mass remote from the sheet being drawn, combinedwith means located between such superheated portion and the point wherethe sheet is drawn, which means at to submerge the surface portion ofthe molten mass and -to limit the area of the molten mass which is exosed to the cooling influences of the externaatmosphere. The means forsuperheating the remote portions of the mass may consist of any meansfor supplying gases of combustion at a high temperature to the surfaceof the molten masssuch, for example, as suitably-constructed burners.Preferably the means for submerging the surface of the mass at a mintbetween thesuperheatcd portion and the point of the sheet and also themeans for limdrug the area of the molten mass exposed to the coolinginfluences of the atmos here may 2 be one and the same structure HIM mayalso .be identical with the ineans'forimparting movement to a. part ofthe surface portion of the mass in opposite directions and away from thefaces of the sheet during the drawing operation, and as here shown thesethree sets of means are all combined in one and are illustrated in theshape of a pair of refractory rollers having their peripheries partiallyimmersed in the molten mass and revolving in opposite directions.

Fifth. The invention consists in a bending; roller over which the sheetof glass is bent or turned during the drawing operation, which rollerreceives the power necessary to set it in motion from the frictionalcontact of the sheet of glass acting in conjunction with positive powermechanism. Usually bendingroller's of the character referred to arequite heavy, weighing considerably more than half a ton; If such rollersare mounted on delicate antifrictional bearings, asdescribed in theaforementioned application Serial No.

304,555, the frictional contact of the sheet in most cases will besufficient toimpart revolution to the roller, which revolution will besubstantially uniform with the movement of the sheet of glass. I havefound, however, that with. the varying conditions, such as 00-, our whensheets of different thickness and different degrees of temperature, &o.,are drawn, there is an occasional relative movqv .ment between thesurface of the roller and of the sheet of glass if reliance is placedentirel upon the frictional contact of the sheet wit the roller to drivethe latter. I have therefore devised means whereby power may be appliedto the shaft of the ending-roller, which power, however, just fallsshort of bein suflicient to impart revolution to the ro ler. This isaccomplished, for example, by means of a friction-clutch inter os'edbetween the driving-shaft and the r0 ler-shaft, in which the friction isadjusted to such a rio point that the clutch will slip and fail to drivethe roller, but is nevertheless so great thatzwith very slightadditional ower applied the roller will readily revo ve. This additionalpower is supplied by the frictional contact of the sheet of glass withthe roller. By this means the g'reater' portion of the power necessaryto drive the roller is obtained from asuitable'source of power, andreliance is placed upon the sheet merely to add the overbalancing amountnecessary to produce the revolution.

Finally, the invention consists in certain detailed methods of procedureand constructions of apparatus, which will be hereinafter.

more fully described and then pointed out in the claims.

It will be apparent to thoseexpert in the art that the inventive ideashereinbefore described are capable of finding expression in methods.varying somewhat in detail and that the inventive idea involved in themechanism is capable of receivin a variety of mechanical expressions. Int e accompanyin drawings, for the purpose of illustration on y, I havedisclosed one form of apparatus which may be'employed butsuchillustration is not to be regarded-as defining the limits of theinvention, j reference being bad to the claims for that urpose.

In said drawings, Figure l is a brokendetailed perspective view ofapparatus employed in practicing the invention, and Fig. 2 is a detailedview illustrating aslightlymodified method of procedure. Fig. 3 is aside elevation of the machine, illustrating the means of applying powerto the various parts of the apparatus. Fig. 4 is a central verticallongitudinal section of the apparatus. Fig. 5 is an elevational view ofthe side opposite to that shown in Fig. 3. Fig. 6 is a verticaltransversev section on the line 6 6, Fig. 4. Fig. 7 is a broken planview, partly in section, of that portion of the apparatus lvingimmediately over and contiguous to the workin chamber or pot. Fig. 8 isa sectional (18- -ta1l illustrating a portion of the-apparatus fordriving the bending-roll.

In the drawings like reference-numerals indicate like parts, andreferring to Figs. 4 chamber or furnace of and 6, '1 is a melting anysuitable or usua construction, and 2 is a workin chamber or pot incommunication therewith throu l1 asuitable opening or openings 3,provided in the lower portion of a bridge wall 4. Preferably there aretwo openings 3, one on each side of the working c amber or ot, so thatthe glass passing from the me ting-furnace 1 will enter the workingchamber 2 adjacent to or beneath the edges of the sheet .beingdrawn.suitable or usual means for heatin the working chamber or pot 2 may beemp oved, and as the specific construction of suc ent invention the sameare not shown in the drawings. Mounted within the confines of theworking chamber 2 are a pair of oppositely-disposedrollers 5 5, composedof any suitable refractory material, such as a suitable clay. Theserollers are mounted u on substantially parallel hollow shafts 7 7, estshown in Figs. 1 and 4,) which shafts have their bearings upon theexterior of the working chamber, the shafts extending through the wallsof said chamber, as shown in Fig. 7. The hearings of these shafts arearranged so that the shafts may be each adjusted at each end both in avertical and horizontal direction. Preferably there are mounted on thesu porting structure of the machine suitable frames 8 8, Fig. 5,arranged to slide horizontally on a suitable bearing plauor plates means.does not-form any essentlal part of the pres- 9. Screw-shafts 10, onefor each frame, are mounted to turn in bearings onplate 9, butwithoutlon itudinal movement with relation to said bearings, suchmovement being restrained, as by a collar 11 or other suitable means.These'screws 10 engage corres 0nding female threads on the frames 8 anmay be revolved by any suitable means, the direc tion of movement of theframes depending upon the direction in which the screws are turned, as.will be readily understood. Sliding vertically within the frames 8 arebearingboxes 12 12, and projecting vertically upward from said boxes arescrews 13, which pass through the 'top portion of the frames 8 and areengaged by nuts bearin u on the top of the frames and having han ieels14 rigidly secured thereto, so that by revolving the hand-wheels thebearing-boxes may be elevated or depressed. Each of the shafts 7 has anenlarged bearing-surface 15,(see Fig. 1,) corres ending in shape to aportion of a sphere, w ich rests in a corresponding bearing in boxes 8,which boxes are constructed in two parts in order to admit of theassemblage of the elements. This form of bearing is one well known inmechanics and rovides for the proper horizontal and vertica adjustmentof the shafts one at a time and indeendently at each end of each shaftwithout imparting any strain to the parts, and also permitting of easymovement, even though the adjustments at each end of either shaft maiynot be absolutely identical.

or the purpose of preventing the shafts 7 from becoming unduly heated bythe intense heat to which thev are subjected within the working chamber2, these shafts, as before stated, are hollow, as plainly indicated inFig. 4, and water is circulated. through the shafts, the same beingconducted into the shafts through flexible couplings 15, Fig. 1, andemerging through coup ings '16.

The mounting of the refractory rollers 5 with relation to the mass ofmolten glass in the working chamber is such that the lower peripheriesof the rollers are more or less immersed within the surface of themolten glass, and these rollers are driven at the same rate of speed,but in opposite directions, the direction of revolution of the tworollers preferably being such that their adjacent surfaces move upwarcl,as indicated by the arrows in Fig. 1. Any suitable mechanism for thusdriving the two rollers in opposite directions, but at the same rate ofspeed, may be employed. As here shown, (see Fi s. 3 and 6,) each of theshafts is provide with a sprocket-wheel 17. Power drawn from any sourceis conveyed by variable-speed connections, asa friction-cone 18, to ashaft 19, having thereon a worm 20, engaging a wormgear 21 on shaft 22.Shaft 22 carries a gear 23 keyed thereto and a sprocket-wheel 24. Gear23 meshes with a gear 25 keved to a shaft 26, which shaft carries asprocket-gear .27 of the same dimensions as the sprocketgear .24 on thrshaft 22. It willthus be seen that the two shafts 22 and 26 are drivenin opposite directions, and that'therefore the sprocket-wheels on theseshafts turn in opposite directions. A sprocket-chain 28 passes fromsprocket-wheel 24 over sprocket-wheel 17 on one of the shafts 7 and asprocketchain 29 passes over the sprocket-wheel 27 and thesprocket-wheel 17 on the other shaft 7. Since the s rocket-wheels 1.7are alike in dimensions ant the sprocket-wheels 24 and '27 are alsoalike in dimensions, it follows that the two rollers 5 5 will not onlybe driven in oppoiite directions, but at the same rate of s cc Mountedbetween the rollers 5 and in position adjacent to the edges of the sheetthat is to be drawn are the devices for holding the sheet to uniformwidth and preventing the: narrowing tendency heretofore mentioned.

Any suitable means for this purpose will be within the scope of thepresent invention; but as here shown such means consist of hooks 30 ofrefractory material immersed in the molten mass of glass adjacent to theedges of the sheet being drawn, said hooks being provided with means formanipulatin them so as to impart movement to the mo ten mass adjacent tthe edges of the sheet away from the medial line of the sheet and towardits ed es. The hooks are clamped on the ends of levers 31, Fig. 6,pivoted at 32 to swin ing links 33. By grasping the handle ends 0 thetwo levers 31 they may be manipulated in such a Way as to cause thehooks to dip into the molten mass of glass and move a slight distancetoward the medial line of the sheet, after which; they can as slightlyraised and then drawn outward toward the edges of the sheet, therebyimparting movement to the surface portion of the molten-mass toward theedges of'the sheet, and thus operate to hold the sheet to its uniformwidth. If desired, these hooks may be operatedautomatically instead ofby hand, as shown and described in the aforementioned application,Serial No. 304,555.

As illustrated in Fig. 4, the receptacle 2 is covered over, except for anarrow slot or opening through which the sheet of glass 33 is drawn. Thecover portion of the rece tacle is preferably provided with downwardy-extendin lip portions 34, whose lower lines preferafhly are below theplane of the upper sides of the rollers 5 5, which rollers are placedbeneath and a little bit to one side of said lips 34. The object ofthese downwardly-extending lips is to assist in preventing the heatedgases of combustion which are directed against the molten glass on andto the rear of the rollers from passing over the rollers and injuriouslyaffectin of glass being drawn. In addition to these the sheet Idownwardly-extending lips two shields 35 35 are provided, which shieldsare supported on either side of the sheet of glass being drawn andparallel therewith and between the rollers5 5 and said sheet. The heatedases of combustion which pass over the rol ers5 5 and under the lips 3434, as well as the intense heat radiated from the molten glass carriedup by the rollers 5 5, would so melt down or soften the sheet of glassbeing drawn as to either make it draw very thin or would render thedrawing of the same entirely impracticable, and the shields 35 35 arethereore supplied to protect the sheet of glass at the point immediatelyabove where it is drawn from the destructive influences of the gases ofcombustion and the heat radiated om the rollers. Theseshields arepreferably in the form of flat hollow chambers and are provided withmeans for circulating a cooling medium, as-water, therethrouh, 'Waterbeing supplied, for example,throug pi cs 36 and carried off by pipes 37,a suita is flexible hose 38- being. attached to the said pipes for thepurpose of induction and-eduction of the water. These shields 35-35 arenot for the purpose of coolingeither the sheet of glass bern drawn orthe surface of the molten-glass dying between the rollers. In fact, caremust be exercised to avoid any material cooling of the surface of themolten mass by the action of these shields, since if any ap reciablecooling due to this cause takes p ace it is liable to materially affectthe successful drawing of the sheet. In other words, the elements 35 35-are provided as shields, and shields only, to protect the sheet of lassfrom radiated heat from the rollers andl'the gases of combustiontpassing over said rollers. For the u-rpose o placing said shields atthe proper is'tan'ce above the mol-.

ten mass to efiectual-ly perform their ofiice as shields and yet at thesame time provide against placing them so near the molten mass as toexercise an appreciable cooling effect thereon these shields are somounted that they may be adjusted both in a vertical and a horizontaldirection. One very simple means for this urpose consists in restingthepipes 3c 37,wl 1 or other refractory material 39, Fig. 4. The shieldsmay be readily adjusted toward or from the'sheet of glass along the .topofthese refractory bricks, and their height may be adjusted by using agreater or less number of bricks under the supporting-pipes 36 37 Anysuitable means may be employed for supplying the heat necessary tosuperheat the surface of the molten glass in the working chamber 2 tothe rear of the rollers 5 5. As here shown, thatportion of the moltenmass lying to the rear of the roller 5 nearest to the n-ieltingfurnace 1is superheated by permitting the heated gases of combustionto pass 1from the melting-furnace 1 over the top of ich support the shields, uponbricks IIO the bridge-wall 4 against the roller, and then to pass upwardand outward through suitable lines, as indicated by the arrows, and intothe downwardly-leading stack 40. (Indicated by dotted lines in Fig. 4.)The means for superheating the glass to the rear of the other roller, ashere shown, consist. of burners 41, Fig. 1, located in'a chamberadjacent to the working chamber 2, and provided with a fine 42, throughwhich the gases of combustion are conducted to the rear of the rollerfi,after which they are conducted by return-fines to the downwardly-leadingfine 43, and hence to asuitable stack 44.

Referringto Figs. 1, 3, 4, and S, is abending-roller located in heatedchamber 46 and carried on a shaft 47, \ivhose ends extend through thewalls of the chamber 46 and are carried on suitable antifrictionalbearings located in bearing-boxes 48. The shaft 47 is hollow and isprovided with suitable means for conducting a cooling mediumtherethrough-for example, the pipe 49, Fig. 1,'

leadin from a source of water-supply and a sultab fe corresponding pipeat the opposite end leading to the sewer or other waste. Se-

cured to the shaft 47 is a sprocket-wheel.

over which a sprocket-chain 50 passes as well as arounda secondsprocket-wheel 51 on a shaft turning in bearings 52, whicl'i lattershaft has keyed thereto a worm-gear 53, which is engaged by a worm 54 onshaft 55, turning in bearings 56 and having keyed thereto friction-disks-57 and 58. The disk 57 is fixed on the shaft and the disk 58 is free toslide longitudinally thereon, but compelled, like disk 57 to revolvetherewith. Mounted loosely on the shaft 55, between the disks 57 and 58,is a sprocket-wheel 59, over which asses sprocket-chain 60, leading tothe driving-shaft 19. Bearing on the disk 57 is s ring 61, which reactsbetween said disk and tie flange 62 on a nut 63, threaded on the.

outer end of the shaft and provided with a hand-wheel 64. By turning thehandwheel 64 in. the proper direction the spring 61 may be compressed,and hence the disk 58 I forced so as to grip the sprocket-wheel 59 withincreased friction between the two disks 5? and 58.

By reference to Fig. 1 it will be seen. that the shaft .47 of thebending-roller is provided with a hand-wheel 65.

It will be readily seen that by adjusting the friction of the disks 57and 58 upon the sprocket-wheel 59 the same mav be brought to a pointwhere the friction will be just below the point necessary to drive'orrevolve the bending-roller 45, the friction-disks slipping on thesurface of the sprocket-wheel 59. By feeling of the hand-wheel 65 and bythe addition of a very slight amount of power by hand to revolve thesame the'o erator can ascertain when the friction of tie disks 57 and 58on the sprocket-wheel 59 has reached the point where a slight additionalamount of power will be suflicient to revolve the'bendingroller. Itbeing known in advance what additional power will be furnished by thesheet. of glass as it passes over the bendingroller the mechanism. is soadjust-ed that this additional amount of power will be sufficient torevolve the roller in unison with the movements of the sheet. The bestresults are obtained with this frictimi-clutch device when the disks 57and 58 are revolving much more ra iidly than it is desired to turn thebendingroiler 45, so'that even when the'friction is suflicient incombination with the action of the sheet of glass 'torevolvethe'rollerthe friction-disks 57 and 58 will be slipping upon thesprocket-wheel 5th When warming up the machine previous to Y beginningthe operation of drawing a sheet of glass, the disks 57 and 58 arepressed with sufficient friction against the sprocket-Wheel 59 to aloneturn the bending-roller 45, and when the. machine is read for thedrawing to begin the friction is eased through the handwheel 64 untilthe friction will be just below the point necessary to drive thebendingroller, the action of the sheet passing there over beingsufficient to furnish the additional power required. 7

In order to avoidthe tendency of the molten glass to pile up at the ends'of the rollers 5 5 and around the shafts thereof,

which tendency if continued might result in a clogging action betweenthe ends of the rollers and the walls of the working chamber, I provideburners 66, which pass through the walls of the working chamber,preferably at a point immediatelybelow where the shafts 7 of the rollerspass through said walls, said burners being connected with the gassystem to 5 by means ofv suitable piping 67. (See Figs. 1

and 3.)

Immediately to the rear of the drawingchamber 46 is a leer 68, and atthe pointwhere said leer joins the drawing-chamber 46 1 10 there is aremovable door or closure 69. Mounted on the rear of the drawin -chamber46 is a drum operated by suita )le power mechanism, and around this drumis wound chain 70, carrying the bait 71 employed in. 15 starting theoperation.

Any suitable apparatus for continumisl drawing the sheet of glass may beemployed, that herein shown consisting of an endless carrier 72,coacting with grip-bars 73, sup- 2o ported on endless chains 74, whichelements act not only to continuously draw the sheet of glass, but toadvance it through the heating-chamber 46 and into the leer 68. As theselast-described elements form no mater25 rial or essential part of thepresent invention they need not be more ful y described. As here shown,they are. substantially those shown in the previous applications abovementioned. x ,0

For the purpose of enabling the bait 71 to be passed from the rear endof the drawingchamber 46between the carrier and the "gripliars overthebending-roller and down into the meltiin chamberor pot between therollers 5 5 and the shields 35 it is necessary that means should beprovided for temporarily raising the grip-bars out of contact with thecarrier. Such means are clearly shown in Fig. 3, in which 75 75 are theshafts which carrv the sprocket-wheels over which the chains'bearing thegrip-bars pass and by which said chains are driven. These shafts 75 restin bearing-boxes 76 on the exterior of the drawing-chamber, which boxesare suported on substantially horizontal rods 77,

l iaving one end pivoted to the framework of the machine "at 78 andhaving the other end pivoted at- 79 to spring-links 80, carried oncrank-aims- ?81, keyed to shafts 82, to which latter shafts are keyedworm-wheels 83, engaged by worms 84 on shaft 85', to which is keyed ahand-wheel 86..

By turning hand-wheel 86 the operator may revolve the crank-shafts 82,and thereby elevate the links 80, and with them the shafts 75, thuslifting the grip-bars free from the carrier, and the closure 69 beingremoved bait 71 may be passed downward into the leer and forward throughthe heating-chain ber 46, over the bending-roller 45, and down into theworking chamber 2 between the shields 35 35, and the drum carryin thechains .70 being set in motion by suitable power, as by thesprocket-chain 87, Fig. 5,

eading to the source of power, the bait is drawn u ward over the bendingroller through t e heatingchamber 46 between the carrier 72 and thegrip-bars 73 and out ofthe rear end of theheating-chamber, where itisdetached from the sheet of. glass in any suitable manner, as by crackingthe glass from the bait or separating the bait from the chains 70.. Atthis point the hand-wheel 86 is operated to lower the grip-bars 73 intocontact with the sheet of glass, and said sheet being grippedbetween-the bars and-the carrier and power being applied the sheet ofglass is thereafter continuously pulled upward over the bending-rollerand advanced by the grip-bars through the leer 68 over theantifrictional bearin ,s' 88.

By inspection of, *ig. 4 it will be seen that each transverse bar of thecarrier 72 will travel faster as it passes around the sprocketwheelssupporting the carrier than it will during the time when 1t is travelingbetween the supporting sprocket-wheels, and henceif the bars between thesprocket-Wheels are moving at the same rate of spee as the sheet ofglass, as they must, the bars passing around:- the front sprocket-wlieeland coming up into position to receive the glass as it comes from the.ben .ling-roller will be moving. slightly faster than the glass.

o I Now it- 1s essential that the several bars constituting the carrier(during the time when they are in contact with the sheet of glass)should travel at the same rate of speed as the glass, in order thatthere may be no relative movement between the sheet and the carrier,since such movement would result in a marring of the fire-finish of thesheet. Ihave found that if the bendingroller 45 he placed with its uppersurface or highermost point on a level with the u per part of thecarrier the bar 72, Fig. 4, o the carrier will come in contact with thesheet of glass at a time when it is moving slightly faster than thesheet, and is therefore liable to, and sometimes does, slightly mar thefirefinish of the sheet by reason of the rubbing action that takes placejust as the sheet comes in contact with the bar 72. For the purpose ofmaking it impossible for the sheet of glass to contact with the bar 72until said bar has reached its highermost positionthat is, a positionimmediately over the drivin shafF-l mount the bend ing-roller 45 in suea position that the highermost-part of therol er will be above the evelof the carrier, so that thesheet gradually descends from the top oftheroller onto the carrier, as clearly shown in Fi 4. By this meansI insurethe contact of the sheet of glass and the carrier at the time, and onlyat the time, when said carrier and sheet are moving at the same rate ofspeed.

As shown in all the figures except Fig. 2, the refractory rollers movein the direction indicated by the arrows in Fig. 1that is, with theiradjacent surfaces moving upward and then outward. This is the "preferreddirection of movement; but it is not essential,

' since in some cases the rollers 5 5 may move in the reversedirection-that is, with their adjacent surfaces :no ving downward andout ward, as indicated by the arrows in Fig. 2.

It will beunders'tood that all the shafts of the rollers 5 5, thebending-roller 45, the shafts sup orting the carrier, and ip-bars are ma0 hollow and are oonnected by suitable stuffing-boxes with conduits,which conduct a suitable cooling fiuid, as water, into the hollowpipes,suitable eduction or exit pipaes being provided on the o posite ends.this means injury to the s afts of the several parts by the intense heatof the machine is avoide While for the purpose of convenience inillustration I have shown the rollers 5 5, the friction-clutch mechanismfor the bendingroller 45, and the worm-shaft 90 for driving the;mechanism in the drawing chamber as all having power directly from theshaft 19, it

will be readily understood that I may and sometimesido interposevariable speed mechanism between'said"shaft19 and rollers 5 5 and thefriction-clutch mechanism for the bowling-roller, to the end that thespee'dof these. elements may be adjusted to se-ure the best results Ofcourse it is entirely possible to so proportion the parts to the shaft19 as shown in Fig. 3 but in many instances the introduction ofvariable-speed mechanism is preferable.

It will be seen from the foregoing that I have provided an exceedinglysimple method and apparatus whereby a continuous sheet of glass may bedrawn from a mass of molten glass, the width of the sheet maintainedsubstantially uniform, and the appearance on the surfaces of the drawnsheet of ribs or strise avoided, as well as any marring effects of thefire-finish due to a rubbing action of the several parts upon the.surface of the glass. i

It wiil of course be understood that parts of the described mechanism.may be employed without other parts and that thereore my invention isnot limited to the use of all the parts described and operating as awhole. Moreover, it will be readily comprehended by those familiar withthis art that many changes in the form, location, and relativearrangement of the various elcnients described may be made withoutdeparturefrom the spirit of mv invention.

Having thus described my invention, what I claim. is-

1. The method of drawing sheet-glass which consists in reparing a massof molten glass,'drawing a s eet of glass therefrom and simultaneouslyimparting movement to a part of the surface of the molten glass inopposite directions and away from the two aces. of the sheet.

2. The method of drawing sheet-glass which consists in preparing a massof molten glass, drawin a sheet of glass therefrom and simultaneousyimparting movement to a art ofthe surface of the molten glass away fromeach face and also away from each edge of the sheet. v

3. The method of drawing sheet-glass which consists in continuouslydrawing a sheet of glass from a mass of molten glass, and continuouslymoving a portion of the surface of the molten mass away from the twofaces of the sheet as drawn.

4. The method of drawing sheet-glass, which. consists in; continuouslydrawing a sheet of glass from a mass of molten glass, and continuouslymoving a portion of the surface of the molten mass away from the twofaces and. the two edges of the sheet as drawn.

5. The method of drawingsheet-glass, which consists in continuouslydrawing. a sheet of glass from a mass of molten glass, continuouslyreplenishing the supply of molten glass as the drawing proceeds, andcontinuously moving a portion of the surface of the molten mass awayfrom the two faces and the two edges of the sheet as drawn.

6. The method of drawing sheet-glass,

.which consists inpreparing a mass of molten which consists in drawing asheet of glass from a mass of molten glass, and continuously submergingthe surface portion of the molten mass on each side ofthe sheet beingdrawn. I

7. The method of drawing .sheet glass which consists in preparing a massof mol 1' en glass, superheating a portlonof the surface of said moltenmass, shielding a portion of said surface from said superheating effect,7 drawing a sheet of glass from said shielded portion andsimultaneouslycausing a part of the same shielded surface to move in 0p0- site directions and away from the faces of the sheet being drawn.

8. The method of drawing sheet-glass which consists in preparing a massof molten glass, superheating a portion of the surface of said mass,shielding a portion of said surface from'said superheating effect,drawing a 8 sheet of glass from said shielded portion, causing thesurface to move outward or in a direction away from the center towardthe edges of the sheet, and simultaneously causing part of the surfaceof the molten mass oposite the faces of the sheet to move away rom saidfaces. I

9. The method of drawing sheet-glass glass, heating a P01131311 of thesurface above the point which it should have for drawin into sheet form,separating a portion of sai surface and subjecting it to the action ofthe atinos here whereby its temperature is low ered, rawing a sheet ofglass from said sep- 1 arated portion, and imparting movement to part ofthe surface of said separated portion away from the faces of the sheet.

10. The method of drawing sheet-glass which consists in preparing a massof molten r glass, superheating a portion of the surface thereof,subjecting another portion of the surface of said molten mass to thecooling action of the atmosphere, drawing a sheet of glass from saidlast-named portion, moving a 1 part of said cooled surface away from theaces of the sheet being drawn and returning it to said superheated area.

1]. The method of drawing sheetglass which. consists in preparing glass,superheatin two parts of the area of the surface of sai .mass, slowlysubmerging and advancing said superheated portions to sin-intermediatearea ex osed to the cooling influence of the atmosphere and drawing a 1sheet of glass from said intermediate area.

12. The method of drawing" sheet-glass which consists in preparing amass of molten glass, superheating two parts of the areaof the surfaceof said mass, slowly submerging 12 and advancing said superheatedportions to an intermediate area exposed to the cooling influence of theatmosphere, drawing a sheet of lass from said intermediate area and s1-niu taneously moving parts of the surface of i 0 a mass of molten 1 r 5said intermediate area away from the faces of the sheet being drawn andreturning them to said superheated areas.

13. In a machine for drawing sheet-glass, the combination of areceptacle containing molten glass,vmeans for drawing a sheet of glasstherefrom, and means simultaneously imparting movementlto parts of thesurface portion of themolten mass away from the two faces of the sheetas it is drawn. 7

14. In a machine for drawing sheet-glass, the combination of areceptacle containin molten glass, means for'drawing a sheet 0 glasstherefrom, andameans simultaneously imparting movement to parts of thesurface ortion of the molten mass away from each ace and each edge ofthe sheet as it is drawn.

15. In a machine for drawing sheet-glass,

the combination of a receptacle containing:

molten glass, two parallel rollers revoluble in opposite directions withthe lower partoi their peripheries immersed in the molten lass, andmeans for drawing a sheet of glass 'orn the molten mass between saidrollers.

16,. In a machine for drawing sheet-glass,

N the combination of a receptacle containing molten glass, two parallelrollers revoluble in opposite directions with their adjacent surfacesmoving upward and the lower part of their. peripheries immersed in themolten glass, whereby a portion of the mass of mo'l ten glass is carriedover and outward by said rollers, means for revolvin' both'ofsaid'rollers at the same speed, an meansa for draw ing a sheet of lassfrom the mass of glass between said rol ers.

17WIn a machine for drawing sheet-glass, the combination of areceptacle-containing molten glass, two parallel rollersrevoluble inopposite directions with their adjacent-sun faces moving upward and thelower part of their peripheries immersed in the molten glass, means forrevolving said rollers, means or adjusting the rollers toward and fromeach other, and means for drawing a sheet of glass from the molten massbetween said rollers.

18. In a machine for drawing sheet-glass,

the combination of a receptacle containing molten glass; two parallelrevolving rollers with their adjacent surfaces moving upward and thelower partof their peripheries immersed in the molten glass, meanssupplying heat to the rear sides of said rollers, and means drawing asheet of lass from the molten mass between said rol crs.

1'9. In a machine for drawing sheet-glass,

the combination of a receptacle containing molten glass, two parallelrevolving rollers with their adjacent surfaces moving upward and thelower part of their peripheries immersed in the molten glass, meansdrawinga sheet of glass from the molten mass between.

.said rollers, means supplying heat to the rear eseeae sides of therollers, and means protecting the sheet from said heat.

20. In a machine for drawing sheet-glass, the combination of areceptacle containing molten glass, two parallel revolving rollers withthe lower part of their peripheries immersed in the molten glass, meansfor vertically and horizontally adjusting said rollers, and means fordrawing a sheet of glass from the molten mass between'said' rollers.

mass of molten glass, means for drawingv a sheet of glass of uniformwidth therefrom,a

roller over which said sheet-is bent as drawn,

and power devices tending to but fallin short of revolving said roller,the friction'a contact of the sheet with the roller supplying theadditional power necessary to revolve the roller.

22. In a machine for drawingsheet-glass, the combination of a receptaclecontaining a mass of molten glass, means for drawing a sheet of glass ofuniform widththerefrom, and a bending-roller driven by theilombinedaction of power devices and the friction of said sheet as it is bentover said roller;

23. In a machine for drawing sheet-glass, the combination of areceptacle containing a mass of molten glass, means for drawing a sheetof glass of uniform width therefrom, a roller over which said sheet isbent as drawn, power devices tending to revolve said roller, and a slipconnection betweensaid devices and roller. i 24. In a machine fordrawing sheet-glass, the combination of a receptacle containing a massof molten glass, means for drawing a sheet of glass of uniformwidth.therefr on1,a roller over which. said sheet is bent as drawn, powerconnections tending to revolvesaid roller, and a'friction-clutchinterposed in said connections.

25. In a machine for drawing sheet glass,

the combination of a receptacle containinga f mass of molten glass,means for drawing a sheet of uniform width therefrom, a' roller overwhich said sheet is bent as drawn, a lever device attached to the shaftof said roller, power devicestending to revolve said roller, and yieldin,"connections between said power devices am said roller;

'26; In a machinefon drawing sheet-glass,

the combination of a receptacle containing a mass of molten glass, meansfor drawing a sheet of uniform wldth therefrom, a roller over which saidsheet is bent as, lrawn, a

hand-wheel attached to theshaft of said roller, power devices tending torevolvesaid roller, and yielding connections between said power devicesand saidroller. 2711x1 0; machine for drawing sheet-glass,

the combination-of a receptacle containing a mass of molten glass, meansfor drawing: a

mass of molten glass, two parallel rollers resheet of glass of uniformwidth therefrom, power devices, and a roller over which said sheet isbent as drawn and receiving driving power from the sheet and from saidpower devices.

28. In a machine for drawing sheet-glass, the combination of areceptacle containing a mass of molten glass, means for drawing a sheetof glass therefrom, means imparting movement to parts of the surfaceportion of the molten'mass away from each face of the sheet as it isdrawn, and a roller over which said sheet is bent as drawn and receivingdrivin power from the sheet.

29. n a machine for drawing sheet-glass, the combination of a receptaclecontaining a mass of molten glass, means for drawing a sheet of glasstherefrom, means imparting movement to parts of the surface ortion ofthe molten mass away from each dice of the sheet as it is drawn, powerdevices, and a roller over which said sheet is bent as drawn andreceiving driving power from said sheet and from said power devices.

30. In a machine for drawing sheet-glass, the combination of areceptacle containing a mass of molten glass, two parallel rollershaving a portion of their peripheries immersed in said molten mass,means for drawing a sheet of glass from the molten mass between saidrollers, and 'a roller over which said sheet is bent as drawn andreceiving driving power from said sheet.

31. In a machine for drawing sheet-glass, the combination of areceptacle containing a mass of molten glass, means for drawing a sheetof glass of uniform width therefrom, a roller over which said sheet isbent as drawn, and a sheet-receiving carrier moving in a plane below thetop line of said roller.

32.' In a machine for drawing sheet-glass, the combination of areceptacle containing a mass of molten glass, means for continuous!drawing a sheet of glass of uniform widt therefrom, a roller over whichsaid sheet is bent as drawn, and a continuously-moving sheet-receivincarrier in a plane below the top line of said roller.

33.- In a machine for drawing sheet-glass, the combination of areceptacle containing a volving in opposite directions with a ortion oftheir peripheries immersed in sai mass, means for drawin a sheet ofglass from the mass between sai rollers, means directing a high heatagainst the rear sides of said rollers, and means shielding the sheet ofglass from said heat.

34. In a machine for drawing sheet-glass,

the combination of a receptacle containing a mass of molt n glass, twoparallel rollers revolving in opposite directions with their peripheriesimmersed in said mass, means for drawing a sheet of glass from the massbetween said rollers, means conducting hot products of combustion aainst the rear sides of said rollers, means to t e rearof said rollersconduct-ing said products to a suitable .means directing a cooling fluidthrough the shafts of said rollers, and means drawing a sheet of glassfrom said molten mass.

36. In a machine for drawin sheet-glass, the combination of a receptac efor molten glass, two parallel rollers mounted with the ower part oftheir peripheries in the molten glass, means for drawing a sheet ofglass of uniform width from the molten glass between said rollers, twohollow shields mounted above said molten glass, one between each rollerand the sheet being drawn, and means for circulating a cooling mediumthrough said shields.

37. In a machine for drawing sheet-glass, the combination of areceptacle containing a mass of molten lass, means for drawing a, sheetof glass 0 uniform width from said glass, two rollers mounted one oneach side of the said sheet with their eripheries dipping in said moltenglass and t eirshafts ro ecting outward through the walls of saidreceptacle, and means su plying a high-temperature in said receptacieadjacent to-the ends of said rollers,

38. In a machine for drawing sheet-glass, the combination of areceptacle containing a mass of molten lass, means drawing a sheet ofuniform width from said mass, two rollers mounted on hollow shafts andwith their peripheries dipping into said molten mass on each side ofsaid sheet, means directing a cooling medium through said shafts, andburners directing a jet of flame into said rece tacle adjacent to theends of, said rollers.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

- IRVING W. COLBURN. Witnesses:-

E. WASHBURN, RICHARD ZINKERNAZEL.

